Apparatus for the high-voltage windings of electrical machines



F. HABEBLI ANDLKUBLER. APPARATUS FOR THE HIGH VOLTAGE WINDINGS OF ELECTRICAL MACHINES.

' APPLICATION FILED JULY 30.1920. 1,387,389.

Patentd Aug. 9,1921;

UNlTEDSTAT-ES PATENT OFFICE.

rnrrz HIL'BERLI, or ENNETBADEN, AND JOHANN KI'iBLER, 0F BAJDEN,-SWITZERLAND,

ASSIGN'ORS TO AK'IIENGESELLSGHAFT BROWN BOVERI & QIE, OF BADEN', SWITZ- ERIAAND.

AI'PARATUS FOR THE HIG'HrVOLTAGE WINDINGS OF ELECTRICAL MACHINES.

Specification of Letters Patent.

(GRANTED UNDER IROYISIONS OF THE ACT: QB MARCH 3, 1921, H STAT. L, 1313.)

To all w loom, it may concern Be it known that we, FRITZ HZ LBERLI, a

citizen of the Swiss Republic, residing at I Ennetbaden, Switzerland, and JOHANN Kins- Electrical Machines, (for which I have filed applications in Switzerland July 19, 1919, No. 86,629, and in Germany June 17, 1920,) of which the following is a specification.v

At the edges and corners of the metal parts of electrical machines in the neighborhood of the spot where the high-voltage windings emerge from the iron, there frequently occur glow or brushdischargesthat may lead to the destruction of the insulation of the coils.

The improved apparatus forming the subject matter of this invention, is designed to prevent the occurrence .of such discharges and the consequent risk of destroying the insulation of the coils. This is achieved by providing the coil, at the spot Where it emerges from the iron, with a conducting covering that projects beyond the mass of iron and is conductively connected to the said mass; the outer edge of said covering projecting from the iron beingtbedded under a-layer 'of insulating material. i

By a covering of this nature, the surface of the coil, at the spot where it emerges from the iron into the air, is brought artificially to the potential of the stator iron, that is to say, to earth potential, so that the boundary of the parts brought to earth potential in the neighborhood of the point of emergence of'the coil, instead of being constituted, by the edges of the teeth, pressing fingers or pressing plates as hitherto, is now v constituted by the edge of the conducting covering of the coil, and has thus been shifted from the aforesaid sharp parts outward to the surface of the coil. No discharges can occur between the coil which is providedwith an earthed covering at the spot where it emerges from the iron, and.

adjacent metal parts which are connected to the framing of the machine and are thereby likewise earthed.

On the contrary, all discharges of the coil are directed toward the edge of the conducting covering. Such discharges can be effectively suppressed by embedding this edge in a layer of insulating material. "it is advisable, also, to ,make this edge of rounded-up shape sov that it constitutes a ring of rounded cross section, surrounding the coil. J

The practical construction of the improved apparatus may be effected by providing the coil at the spot where it emerges from the iron, first witha tight-fitting conducting covering, for instance, by pasting Patented Aug. 9, 19921. Application filed Jul so, was. Serial no. access.

tin-foil upon it, or giving it a coating of metallic or conducting material, and then slipping over the saidv covering or coating,

a tight-fitting sleeve of electrically conduct iog material.

In the accompanying drawings Figure 1 shows one way of carrying out the invention with a sleeved consisting of one piece, and

rig. 2 another way with a sleeve consist- ,ing of two pieces d, and 01 y The insulated coil a is provided, at the spot where it emerges from the statorii'on b,-with a tight-fitting conducting covering 0 over which a sleeve (1 of conducting material is slipped. The .outer edge of this sleeve,

projecting from the iron, is provided with a ring (2 which surrounds the tube, and is cated by d, and 01 in Fig. 2, but in other respects the corresponding parts are lndb cated by the same reference letters asv in Fig, 1. V

What we claim is inclosed on all sides by the insulating ma- 1. An apparatus for the high voltage windings of electrical machines including a stator, an insulated high tension conductor emerging therefrom and an electrically conducting covering of said insulated conduc tor, one end of the conductingicovering'being connected electrically to t e stator, the

other end being removed spacially from the stator and protected from exposure to the air by an insulating sheath.

2. An apparatus as claimed in claim 1, characterized by the feature that the outer edge of the. conducting covering, that is bedded under the layer of insulating material, is formed with a bead-like rounded cross-section surrounding the coil.

3. An apparatus as claimed in claim 1, characterized by the feature that the conducting covering is composed of a conducting layer at the surface of the coil and of a two-part sleeve of conducting material having an outer edge, of a bead-like crosssection the two parts or halves of said sleeve being slipped from opposite sides over the conducting layer and on to the coil, so that, when brought close together, the said two parts will constitute a tight-fitting ring surrounding the coil.

In testimony whereof We have signed our names to this specification.

FRITZ HABERLI. JoHAN-N KUBLER. 

